I am writing this at the end of a day where the temperature in Adelaide reach 42.6 degrees celcius and even Mt Barker was expecting 40 degrees. This is a scorcher and the reality is that we have had a rather mild summer so far, with only a few scorching days and not a run of them like we had a few years ago. In December 2015 Adelaide had seven days over 40 degrees celsius and there were 13 days over 40 degrees the summer before that.
Today I ventured out in the baking sun in the middle of the day to play with my Christmas present – a laser thermometer. I wandered around my property and took temperatures of lots of things but the most striking was the temperature of the pavers which are in full sun all day – they were 55.8 degrees. Now even if my thermometer is a few degrees off, that is still extreme. The temperature of my rubble driveway was slightly better at 42.8.
By contrast though the temperature of was my front lawn in the shade – it was 21.3 degrees, significantly less than that of the pavers. Now the reality with this lawn is that it is not a really cool, lush lawn and the shade is only a relatively small area of dappled shade under my young jacaranda, perhaps only three metres across. In hindsight I should have taken lots more temperatures for comparison, like that of my back lawn which is lush and long soft leaf buffalo (I was waiting for today’s heat to pass before I mow it). I am sure this back lawn would have been cooler still. In hindsight I should have also taken temperatures of garden beds in the shade, but by the time I thought of these the heat had passed.
Planners in Adelaide, as well as many other hot cities around the world, are concerned about the heat island effect caused by the mass of heat absorbing hard surfaces and are trying to factor in a wide range of trees and green life in the urban environment to try and reduce this. Often in the Hills we think we are not subject to the problems of the city, after all usually our temperatures are a few degrees cooler than those on the Plains. Yet as I drive around The Hills and look at new homes and developments, I am concerned by the
dominance of the houses and hard landscaping such as pavers, concrete and retaining walls, all things which absorb heat and make the temperatures that much more extreme. There is often a lack of trees and sometimes no lawn or instead a fake lawn (which can get just as hot as pavers, so don’t be fooled).
Sometimes the lack of trees and garden is because the blocks are smaller, or in fact, that the house has a bigger footprint on the block. However there are still things you can do in your garden to reduce the heat around your home. My suggestion for everyone with a sunny property, no matter where you live, no matter how big your outdoor area, no matter what the aspect, is to take a look at your space and firstly work out where you can create natural shade with an appropriately sized tree or large shrub, or vine covered pergola
or large archway. Sometimes people create covered pergolas with tin or polycarbonate roofing, however this does not create cool shade and can in fact create a very hot space. Secondly try to reduce or at least rationalise the amount of hard, exposed heat reflecting surfaces around your property. Some paving for driveways and paths is necessary and practical, but huge areas of paving is simply increasing your temperature. Also if the sun beats down on the wall of your house, work out how you can grow a suitable plant to cast shade on that wall. It might be a tall shrub or even a climber on a mesh screen. To me, to provide relief from our harsh summers, our garden should be a lush cool oasis.
The hotter it gets in your yard, the harder it is for adjacent plants to grow, the more water they may require to get established and continue to thrive and survive, and the less likely you are to use the space in hot weather. Going inside, the hotter it is outside your home, the more air conditioning you will need to keep your house cool, and the more likely you will have all your blinds down and curtains shut to keep out the heat.
Why have a garden at all if you shut yourself inside?
So it might cost you some water to establish a garden, but it will save on your power bills, and don’t forget that a good garden increases the value of your property anyway. In 2011, research by Husquvana, the global outdoor power products company, quantified this return on investment for Australian property owners, by stating that “Australians who invest in a well-kept garden can expect it to increase their property sale price by 12 percent”.
Now creating shade and shelter from the heat doesn’t happen overnight. It takes a few years and mid-summer is definitely not the time to be planting. Instead, look around your town and other areas in the Hills and look at gardens which are cool, get advice from your local nursery or garden centre, and plan to get started this autumn so in a few years’ time you can beat the heat.